1. Field of the Invention
The present invention pertains generally to hopper outlet door frames, which are adapted for use in connection with railroad hopper cars, and through which lading within the car is adapted to be discharged by gravity.
2. Description of the Prior Art
A hopper outlet door frame is mounted in the outlet opening (usually trapezoidal) of the hopper section of a railroad hopper car, and swingably supports a door (usually rectangular) adapted to open or close the door frame opening. Existing hopper outlet door frames are cast from steel in one piece. This manufacturing procedure requires not only expensive foundry patterns which are subject to shrinkage and warping, but also different sets of patterns for each different frame size and shape.